DE 10 2009 048 813 describes a tap changer for uninterrupted switching between winding taps of a tapped transformer. The tap changer has two load branches each comprising a vacuum interrupter acting as a main contact and parallel thereto a series circuit of a switching-over resistance and a vacuum interrupter. The winding taps can be connected with a common load output line by the load branches. Mechanical switching elements serving as additional isolating switches are arranged between the vacuum interrupters of the two load branches and the load output line. It is possible by the mechanical switching elements to electrically separate the respective interrupter from the load output line in a load branch not conducting the load current and thus to increase the surge voltage strength of the tap changer.